Embodiments of the invention generally relate to electronic trip units, and more particularly to limitation of read/write access to information stored on electronic trip units.
Circuit breakers may be used in industrial, commercial, and residential applications for protecting electrical devices from over-current situations. Circuit breakers may be used as a replacement for conventional fuses, although some circuit breakers function slower than fuses, and may include complicated mechanical components. Further, time-delay and other advanced fusing techniques may be complicated to implement in the mechanical components of typical circuit breakers. Solid-state trip units, or electronic trip units, have been included in circuit breakers for some advanced functionality. For example, electronic trip units may perform functions such as adjustable instantaneous tripping, adjustable delayed tripping, and may provide increased flexibility if compared to typical stand-alone circuit breakers.
However, settings for advanced functionality (for example, sensitivity, time delay, etc.) provided by conventional electronic trip units are user-adjustable. Further, both technically apt and in-apt personnel may have access to these user-adjustable settings. Adjustment of the settings may be necessary to detect fault conditions or issues with operation of the electronic trip unit. Additionally, it may be necessary to periodically monitor the settings, or gain access to performance related data stored on the electronic trip unit. However, the settings and/or data may be proprietary or protected information, and it may be desirable to limit access to these settings and/or data.
Conventionally, protective casings have been employed to limit access to electronic trip units. For example in FIG. 1, a conventional electronic trip unit 1 with protective casing 2 is illustrated. As shown, the protective casing 2 may include a hinge 4 and locking device 3. To limit access to the electronic trip unit 1, the locking device 3 may include a key-slot or other locking mechanism needing a valid key. Only a valid key may be used to open the protective casing 2, and therefore, only personnel with the valid key may access user-adjustable settings on the electronic trip unit 1.
However, it is appreciated that the protective casing 2 may be broken, or altered, to allow access to the electronic trip unit by anyone. Further, if the valid key is lost or misplaced even authorized personnel may have difficulty accessing the user-adjustable settings of the electronic trip unit 1 or other information stored thereon. Therefore, read/write access to conventional electronic trip units may be unlimited.
Accordingly, example embodiments of the present invention may provide read/write access limitation of electronic trip units to overcome these drawbacks.